The House of Habsburgs was a powerful monarchy that ruled territories across Europe from 1526 to 1918. Through strategic marriages, the Habsburgs gained control over the Holy Roman Empire, Spain, Austria, parts of Italy, the Netherlands, and other lands. By the early 16th century, their vast empire was in constant conflict with the expanding Ottoman Empire to the east. In 1521, the House of Habsburgs split into junior and senior branches to govern these separate territories.